Zacuto is running a 3 episode series on HDSLR cameras: the Canon 5D, 7D, 1D, the Nikon D3s, Panasonic GH1. The last episode checks out low light / high ISO scenes. They even test Hyper-ISO in the “BIC lighter scene”: 640, 1250, 2500, 5000, 10000, 25650, 51200 and 102.000 ISO!!
It is clear that low light (under 1 foot-candle) conditions is where HDSLR cameras shine. They certainly say a lot of positive things about the Nikon D3s, that can film at the unreal 102.000 ISO.